1. Field of the Invention
The present invention relates to joining systems and to structural members for use in such joining systems. More particularly, the present invention relates to structural members which have gripping features formed on the lower and upper base plates which inhibit the vertically oriented stud from inadvertent slippage, movement and/or migration within the lower and upper base plates.
2. Background of the Invention
Traditionally, light weight construction of metal stud frames employs steel or aluminum stud members which are generally channel shaped and wherein the ends of the stud members engage channel shaped plate members. A standard form metal stud frame will usually comprise a series of spaced apart stud members which each engage via their ends respective opposing top and bottom plate members. According to conventional methodology, the frames are generally assembled on the ground. Typical frame construction involves placement of top and bottom plate members in spaced apart opposing relationship whereupon stud members are connected to the top and bottom plates which traditionally involves engaging the ends of the stud with tech screws or the like. These frames may or may not be braced but in the case where they are not braced with bracing members reliance for bracing is placed on tech screws. Unlike external frames, internal frames used in partitioning are not generally braced during construction as bracing is affected by wall cladding fixed to the frame. During construction, stud frames are structurally weak and in the case of internal frames, they are not effectively braced until the wall cladding is affixed to the frame. A small number of holding screws may be used to fix some studs to the top and bottom plates. Although a weak form of bracing is created by the conjunction between stud and plate members which are screwed, no reliance can be placed on the bracing of the frame as the unscrewed joins do not offer sufficient strength and resistance against slewing in the circumstance when the frame is lifted into position.
Installers screw the members together at the point of overlap between stud and plate but engagement of studs to plates with limited screwing will not of itself provide adequate bracing. The profiles of the known studs and plates are channel shaped with a planar base and sidewalls extending from and continuous with the edges of said base. Typically, a stud mates with a plate by insertion of the end of the stud into the throat of the plate. The fit is essentially friction grip and there is no resistance against separation of stud from plate until such time as tech screws are inserted.
Another method of affixation of studs to top and bottom plates involves a tab and slot arrangement in which tabs located at the extremity of the walls of the top and bottom plates engage a corresponding slot in each wall of the stud members following which the tradesman hammers the tabs so they are oriented at an angle other than normal to the walls of the stud members thereby locking the stud members against the top and bottom plates.
One advantage of this method is that more material is required to form the channel shaped top and bottom plates. Secondly, additional labor is required to bend the tabs into their locking position which can be awkward due to the position of the protruding tabs inside the channel shaped studs. Although the tab and slot method of connection of studs to plates is effective in securing the members, it is tedious and time consuming for tradesman to bend the tabs four times for each stud. The insertion of tech screws, although used in holding studs to plates during construction and until the cladding material is affixed to the stud frame is likewise time consuming and does not provide effective temporary bracing until all or the majority of the joins are screwed. Other methods of affixation of studs to plates have been used such as riveting, welding or clinching of each stud, all of which methods involve additional labor.
A further prior art method of joining structural members for a stud frame involves the use of cooperating and corresponding engaging formations in the walls of both stud and plates. The formations in the plate consist of a securing notch formed in the walls of the mating stud and plates. To facilitate stud location, the wall extremities of the plate are abbreviated by upturning of a lip formed at the extremities at the position where the stud mates with the plate. The additional material required to form the lip adds to material costs and necessitates a securing clip which adds to costs in labor and assembly. Another disadvantage of this mode of connection is that the surface area of engagement is low resulting in low resistance to relative rotation, twisting, and pulling out between stud and plate.
Another prior art method involves the engagement between a formation in the walls of the top and bottom plates and a corresponding formation in stud members. The formations are produced by pressing out of a region of the wall of each member so that the formations mate in snap fit male/female relationship. While this system works well, it necessitates an additional punching step during production which increases production time of the constituent structural members but it does not provide a useful and more convenient alternative to the tab system described above. All of the above systems rely on pre-punching and limits or removes entirely the ability of the installer to move the studs relative to plates once fitted and where adjustment may be required during construction to accommodate fit and finish errors or window or door size irregularities.
Another problem arising particularly in internal stud frame construction is irregularity in floor to ceiling height in buildings caused by poor concrete finishing and out of alignments which often necessitates cutting of stud members in regions of reduced height. In a normal stud frame, the stud members would be the same height or length but where there are irregularities in the ceiling or floor, the frame will not fit unless stud heights are suitably cut to accommodate those differences. This is time consuming and adds additional labor costs to the installation. Finally, another disadvantage of the known prior art is that the vertically oriented studs are prone to sliding, slipping, movement and/or migration within the lower base plate and upper base plate, particularly, while routing conduit through conduit ports. For instance, when the conduit is being pulled through the conduit ports formed in the vertically oriented studs, the conduit tends to catch and pull the studs from their predetermined spacing. Therefore, it would be beneficial to provide a gripping feature or the like, which will inhibit such unwanted sliding, slipping, movement and/or migration within the lower base plate and upper base plate.